Lieutenant general, lieutenant-general and similar (abbrev Lt Gen, LTG and similar) is a military rank (NATO code OF-8) used in many countries. The rank traces its origins to the Middle Ages, where the title of lieutenant general was held by the second in command on the battlefield, who was normally subordinate to a captain general.

In modern armies, lieutenant general normally ranks immediately below general and above major general; it is equivalent to the navy rank of vice admiral, and in air forces with a separate rank structure, it is equivalent to air marshal. A lieutenant general commands an army corps, made up of typically three army divisions, and consisting of around 60,000–70,000 soldiers (U.S.).

The seeming incongruity that a lieutenant general outranks a major general, (while a major outranks a lieutenant), is due to the derivation of the latter rank from sergeant major general, which was also subordinate to lieutenant general. In some countries, (e.g. France and Italy), the ranks of corps general or lieutenant colonel general are used instead of lieutenant general, in an attempt to solve this apparent anomaly – these ranks are often translated into English as lieutenant general.[citation needed]

In a number of states, the rank of lieutenant general is the highest army rank in use. In Latvia and Lithuania, the chief of defence is a lieutenant general, and in the Irish Defence Forces and Israeli forces, the Chief of Staff holds this rank.